Interchangeable Detector Modules for Compact CT Geometry
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Solution Overview
Problem
Traditional computed tomography (CT) systems have a limited ratio of usable field of view to outer diameter and non-uniform resolution, with artifacts from small, high-density objects and edges not being effectively corrected due to detector errors and differential scatter issues.
Innovation Solution
A CT system with a rotating gantry featuring interchangeable x-ray detector modules positioned at varying distances from the x-ray source, allowing for a compact geometry and uniform resolution across the field of view, and a method for correcting image artifacts using a predictor-corrector algorithm to address differential scatter rejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If detectors are placed on an arc centered on the focal spot in traditional CT systems, then the system structure is simple, but the ratio between usable FOV and outer diameter is small
Solution Approach 1:
The detector array is divided into multiple independent detector modules that can be positioned at different distances from the x-ray source. Each module can be independently adjusted along the arc, allowing the system to achieve a larger effective FOV without requiring a proportionally larger overall system diameter, thus improving the FOV-to-diameter ratio while maintaining manageable structural complexity through modular design
Solution Approach 2:
The detector modules are made dynamically adjustable along the arc path, allowing their positions to be changed during operation. This dynamic positioning capability enables the system to optimize the FOV-to-diameter ratio by adjusting detector distances from the source, rather than being fixed in a traditional arc configuration
2Manufacturing precision
If traditional arc-shaped detector placement is used, then the system is easier to manufacture, but resolution is non-uniform across the FOV
Solution Approach 1:
Each detector module is equipped with independent positioning mechanisms that allow precise adjustment of its distance from the x-ray source. This enables local optimization of resolution across different regions of the FOV, with each module adjustable to achieve uniform resolution characteristics, rather than accepting the non-uniform resolution inherent in fixed arc placements
Solution Approach 2:
The system changes the positional parameters of detector modules along the arc, allowing adjustment of source-to-detector distances. By varying these parameters, the system achieves uniform resolution across the FOV while maintaining compatibility with standard arc-based manufacturing approaches
3Reliability
If fixed detector positions are used, then the system structure is simpler, but artifacts from small high-density objects cannot be corrected
Solution Approach 1:
The detector modules can be dynamically repositioned to different locations along the arc, enabling the system to acquire projection data from multiple geometric configurations. This dynamic capability allows the implementation of artifact correction algorithms that utilize data from varying detector-source distances, improving reliability in correcting artifacts from small high-density objects while managing complexity through controlled modular movement
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves a smaller footprint with increased inner diameter for scanning larger objects while maintaining uniform resolution and effectively correcting image artifacts, particularly from small, high-density objects and edges.
Implementation Method 1
an x-ray source projects a fan-shaped or a cone-shaped beam towards an object to be imaged. The x-ray beam passes through the object, and, after being attenuated by the object, impinges upon an array of radiation detectors
Implementation Method 2
Each radiation detector produces a separate electrical signal that is a measurement of the beam intensity at the detector location
Data Source
AI summary
An imaging system is provided. The imaging system includes a rotating gantry. An x-ray source is mounted to the gantry. The system also includes a plurality of interchangeable x-ray detector modules is mounted to the gantry, opposite the x-ray source. The plurality of interchangeable detector modules includes a first detector module mounted at a first distance from the x-ray source and a second detector module mounted at a second distance from the x-ray source. The first distance is different from the second distance.